1. Technical Field
The present invention relates to a headrest and a vehicle seat provided with the same.
2. Related Art
Vehicle seats provided with headrests for supporting the head portion of an occupant are known. With various of these vehicle seats, there is a possibility of the head portion of an occupant seated in a seat to the rear of the vehicle seat moving towards the vehicle front due to inertia during a frontal collision (vehicle frontal impact), with the possibility of the head portion then making contact with the rear portion of the headrest of the vehicle seat. In such cases, for a headrest that is tilted at a small angle of tilt towards the vehicle front, the component force acting on the headrest towards the vehicle front is relatively large when the head portion of the occupant contacts the rear portion of a headrest, and so the seat back supporting the headrest rotates towards the vehicle front, thereby absorbing impact to the headrest. Consequently, the reaction force to the head portion of the occupant is comparatively small.
However, for a headrest tilted towards the vehicle front with a large angle of tilt, the component force acting on the headrest in the vehicle downwards direction is relatively large when the head portion of the occupant contacts the rear portion of the headrest. Also, as described for example in Japanese Utility Model Application Laid-Open (JP-U) No. 63-35651 in which a headrest is provided with a tilting mechanism for adjusting the angle of tilt of the headrest, in a state in which the headrest is tilted towards the vehicle front direction to the maximum extent, the component force acting on the headrest in the vehicle downwards direction is at a maximum when the head portion of an occupant contacts the rear portion of the headrest. Accordingly, since it is difficult for the seat back to rotate towards the vehicle front direction, the amount of impact to the headrest absorbed is reduced, and the reaction force to the head portion of the occupant becomes comparatively large.